Portable talking motion picture apparatus



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T ORNEY April 15, 1941. H. c. HOLDEN V PORTABLE TALKING MOTION PICTURE AFPARATUS 4 Sheets-She et 4 Original Filed Feb. 12,1932

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Patented Apr. 15, 1941 UNITED STATES PATENT OFF-ICE PORTABLE TALKING MOTION PICTURE APPARATU Harold C. Holden, Fairfield, Conn, assignor to Radio Corporation oi America, a corporation oi.

Delaware Original application June 21, 1935, Serial No. 27,761, which is a division of application Serial No. 592,453, February 12, 1932, now Patent No.

2,031,832, dated February 25, 1936.

Divided and this application April 12, 1938, Serial No.

3 Claims.

proved sound reproducer, and an amplifier, all

built into a single, light-weight, inexpensive unit fitted within a sound-proof carrying case.

One object of the invention is to provide an improved talking motion picture apparatus adapted to use 16 mm. film which carries thereon a sound-track oi one of the usual types in commercial use.

Another object of the invention is to provide such an apparatus which is capable of high quality sound reproduction from such a film.

Another object of the invention is the provision of an improved film gate which permits the film to be driven from one row of sprocket holes only without flicker at the aperture and without the film tending to run oilf to one side or the other.

Other and ancillary objects of the invention will be apparent from a reading of the following specification in connection with the accompanying drawings, and its scope will be pointed out in the appended drawings wherein:

Figure 1 is a side view of the projector as mounted in the carrying case and with the carrying case open for threading oi the pro- Jector,

Figure 2 is an elevation corresponding generally to Fig. 1 and indicating much of the interior construction of the device,

Figure 3 is a horizontal section through the mechanism at the axis of the drive motor,

Figure 4 shows a modified form of film gate; and

Figures 5, 6 and 7 show details thereof.

The film with which this projector is intended to cooperate is of the conventional 16 mm. width and is provided with pictures of exactly the same size as are ordinarily used on 16 mm. amateur film. -The main difference from the usual amateur film is that one row of sprocket holes is omitted and a soundtrack, preferably of the variable area type and approximately 93 of an inch in width, is located approximately where the row 01' sprocket holes would have been. Other diiIerences are that the film is made to run at a speed of 24 frames or pictures per second which is the usual speed machine from its case.

in talking motion pictures instead of 16 pictures per second which has heretofore been usual in 16 mm. films. The reason for this is that such pictures can be properly printed by projection when desired from standard theatre films or the equivalent without requiring that a special negative be taken and a special soundtrack be made to be capableof reproduction in this ap-.

paratus.

The projector as shown in Fig. 1 is housed within a carrying case ID. This carrying case as indicated at H lined with appropriate sound absorbing material to absorb any noise which might be produced by the projector mechanism, the motor, or the fluttering of the film in order to avoid. any disturbance of the audience, and is provided with suitable apertures for the lens as at H, for the entrance and exit of wires as at l3, and for the entrance and exit of the film as at H.

The case is also provided with ventilation apertures 90 in-the front, back, and lid, and with a door ill at the back which provides access to the 'amplifier tubes without removing the opens downwardly to provide easy access to the film, side of the machine for threading, etc.

Upon the outside 01' the carrying case are detachably mounted the film reel arms IS, a reel in the lowermost arm being driven by the belt l6 which passes over the rollers ii.

The loudspeaker cable is plugged into the base of the machine as indicated at 209, and when the case is closed and in operating condition passes out through the aperture I3.

After the film has been threaded with the case open, the case is closed and remains in closed position during operation, thereby retaining within the case not only the noise of the projector but also any stray light which may escape from the lamphouse.

The case is "provided with a suitable leveling mechanism which may, for example, be a vertically slidable member retained by the set screw I 8 or the member l8 may itself directly control an appropriate member for raising or lowering the front end of the case.

One form of film gate is shown in Figs. 2 and 3. In this form of gate there is a plate 59 attached to the motor housing in front of the The front oithe case formed contact surfaces for the film and having outwardly extending ears at the top and bottom,; as shown, by which it may be grasped to open it. This gate is held in closed position by the springs 6| against the pressure of which it mayg be opened by grasping the ears above referred to and the elongated apertures in the sides of the gate which engage the pins 62 may then be slid down over the pins 62, retaining the gate in open position.

A modified form of gate is .shown in Fig. 4 and this particular form of gate is found to be peculiarly effective when the film is drawn by traction of the" intermittent feed on sprocket holes on one edge of the film only.

In this gate 'a backing plate 59 is provided as in the gate previously referred to, but the film is pressed toward this by a linear shoe 10. This shoe is provided with ears II which serve the same function as the ears above referred to and these ears are each provided with a notch 12 in their lower edges whereby the pressure shoemay be maintained in open position by drawing it outwardly and hooking these notches over the plates 13, which also serve as spring-retaining members.

The opposite edge of the film is prevented from fluttering by a guide 14 which extends the entire length of the gate but which, instead of being pressed firmly against the film by springs, is set at such spacing from the guide on the backing plate that the film can move freely therebetween. This avoids producing any tension on the edge of the film which is not drawn by the intermittent and at the same time, due to the small clearance (which may be of the order of two one-thousandths of an inch) and acting in cooperation with the pressure shoe at the other edge of the aperture, prevents any flutter of the film at the projection aperture.

The guide 14 is spring-pressed toward the shoe 59 but is stopped by eccentric headed screws 15 mounted at the top and bottom of the gate. This permits the shoe 14 to rise when a splice or other thickened portion of the film passes through the gate and at the same time provides a clearance between the shoe and the film under normal operating conditions.

In order to permit the film to be readily threaded through the apparatus, a bar 16 is rigidly at'-.

tached to the shoe 10 and operates infa slot-in the shoe 14. When the shoe I0 is retracted by means of the ears H, the bars 16 which are provided at both the top and bottom of \the gate likewise retract the shoe H since the movement of the shoe 10 is greater than the length of the slots in the shoe 14, but when the shoe I0 is released and permitted to ride against the surface of the film, the pins 16 move forwardly in the slots when the shoe I4 contacts with the eccentric headed screw 15, and neither of the shoes therefore interferes with the normal operation of the other.

I claim as my invention:

1. A film gate for a motion picture apparatus comprising an aperture plate, a spring-pressed shoe at one edge of the film movable toward and away from said aperture plate, stop means maintaining said shoe at a predetermined distance which is greater than the thickness of the film over said aperture plate, and a second springpressed shoe movable toward and away from said aperture plate at the other edge of said film and adapted to press the film against said aperture plate.

2. A film gate for a motion picture apparatus comprising an aperture plate, a spring-pressed shoe at one edge of the film movable toward and away from said aperture plate, stop means maintaining said shoe at a predetermined distance which is greater than the thickness of the film over said aperture plate, and a second springpressed shoe movable toward and away from said aperture plate at the other edge of said film and adapted to press the film against said aperture plate whereby said film is maintained under pressure and longitudinal tension at one edge only.

3. A film gate for a motion picture apparatus comprising an aperture plate, a spring-pressed shoe at one edge of the film movable toward and away from said aperture plate, stop means maintaining said shoe at a predetermined distance which is greater than the thickness of the film over said aperture plate, a second spring-pressed shoe movable toward and away from said aperture plate at the other edge of said film and adapted to press the film against said aperture plate, and lost-motion connecting means between said shoes whereby the opening of said second shoe for threading opens said first shoe but the closing of said second shoe permits said first shoe to rest against the said stop means.

HAROLD C. HOLDEN. 

